This invention relates to a camera loadable with a film provided with a magnetic recording area.
In conventional cameras, winding of a film or the like is performed by fitting projections provided on the outer surface of a take-up spool in perforations formed in the film. In recent years, there have been proposed films in accordance with a novel system in which pairs of perforations are regularly formed along a film winding direction and exposure areas for recording photographed images and magnetic recording areas for recording specified magnetic data are provided in predetermined positions. In these films, the perforations are not used for the winding, but used as references for the positioning of the exposure area and the magnetic recording area.
Accordingly, cameras using such a film have a problem that a specified magnetic data cannot be recorded in a set magnetic recording area unless a distance the film is fed before the start of magnetic recording after the detection of the perforation is accurately detected.
Also, there is a problem that an image cannot be recorded in a set exposure area unless winding is accurately stopped based on the detection of the perforation.
On the other hand, magnetic recording may be performed during the winding of the film. In such a case, there arises a problem that, when a winding speed varies, magnetic recording cannot properly be performed due to a variation of a bit density or the like.
Further, with the cameras using the films in accordance with the novel system, the magnetic data may be recording during the winding of the film which is performed after each photographing operation.
Generally, the film winding speed largely varies depending upon how much a battery is used up. As described above, the magnetic recording areas are provided in preset positions and an amount of data to be recorded (bit number) is predetermined. Accordingly, if the magnetic data is recorded at a specific frequency, the following problem arises: the magnetic data cannot be recorded in the predetermined magnetic recording area when the winding speed is high, whereas the bit density becomes excessively high, making it difficult to read the recorded data when the winding speed is low.
The magnetic recording areas include frame magnetic recording portions provided in correspondence with the respective frames so as to record data including a photographing information of each frame and a leader magnetic recording portion provided at the side of a leading frame toward the leading end of the film so as to record a title of the film or like information concerning the film. These magnetic recording portions are arranged in specified positions based on the perforations.
In the cameras using the film as above, the film is automatically wound by one frame after photographing is performed. Data may be recording by a magnetic head provided in a camera main body while the film is wound by one frame.
The data recorded in each frame magnetic recording portion include data settable before a photographed image is recorded in the corresponding frame as well as the number of prints to be made or like data which may be changed depending upon how the photographed image is recorded in the frame. In view of data reading at a later stage, the following problem arises: it is desirable to record a change data in place of the data already recorded in the frame magnetic recording portion in the same state as this data was initially recorded.
Film data concerning the film are recorded in the leader magnetic recording portion. In view of collective reading of the film data and the frame data at a later stage, the following problem arises: it is desirable to record the film data in the leader magnetic recording portion in the same state as the frame data are recorded in the frame magnetic recording portions.